In Denver, the robber hit these locations between July 4 and July 9: : -- A Radio Shack at 715 S. Colorado Blvd. --A Subway at 4300 E. 8th Ave. --A Radio Shack at 5305 E. Colfax Ave. --A Hobby Lobby at 920 S. Monaco Pkwy.

An employee at the Denver Radio Shack said the man appeared to be nervous. "He was like shaking. He was holding the gun. He was like shaking. So I knew he was freaked out," said the employee. "He pulled the gun out and was like hurry up. You know. Told me the lay down on the floor on my stomach and wait until he was gone," said the employee.

The manager at Doc's Video told 7NEWS the employee working during the robbery feared the gunman would shoot if he didn't hand over money from the cash register. The employee has taken a leave from work, the manager said.

The Aurora Police Reward Fund is offering up to $2,000 and Crime Stoppers is offering up to $2,000 for the arrest and conviction of the robber. Anyone with information about the robberies is asked to contact Aurora Police Detective Brian McClure at 303-627-3232 or Sgt. Bob Wesner at 303-627-3152.

The man is also wanted in connection for several robberies in Austin, Texas. In one case he told employees at a local store, "I'm sorry to ruin your day, but i'm robbing the place."

Individuals who want to remain anonymous can call Crime Stoppers at 720-913-7867.

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